1. Field of the Invention
The present invention relates to a reel-typed tape cartridge used for a magnetic recording and reproducing apparatus.
2. Description of the Prior Art
A reel-typed tape cartridge used for a magnetic recording and reproducing apparatus is provided with a brake-locking member for preventing a tape reel from being rotated in order to maintain a braked state when the tape cartridge is not used. FIG. 10 is a vertical sectional view of a conventional one-reel typed tape cartridge. A tape cartridge 100 in FIG. 10 is produced so as to prevent the tape from being loosened as follows. A brake-locking member 103 biases a teeth portion 103a using a spring 101 in a direction of an arrow A in FIG. 10, in which a teeth portion 103a of the brake-locking member 103 is mated with a teeth portion 104 being connected to an inner surface side of a hub 102a of a tape reel 102, resulting in that rotation of the tape reel 102 is prevented when the tape cartridge is not used, e.g. when the tape cartridge 100 is preserved, and further the rotation of the tape reel 102 owing to unexpected vibration or the like when the tape cartridge 100 is preserved and the loosening of the tape owing the rotation thereof is prevented. Further, when the tape cartridge 100 is used, a brake-releasing plate 105 is pushed up, thereby lifting the brake-locking member 103 upwardly in FIG. 10 against a biasing force using the spring 101, releasing the mating state between the teeth portion 103a and the teeth portion 104, resulting in performing lock-releasing operation.
FIG. 11A is a partial front view showing a state where the teeth portion 104 at the side of the tape reel 102 is mated with the teeth portion 103a of the brake-locking member 103. FIG. 11B is a partial front view showing a state where the mating state is released. As shown in FIG. 11A, the teeth portion 104 and the teeth portion 103a, both are shaped in an elongated triangle teeth manner, and the teeth of them are mutually mated therewith.
However, according to such a conventional teeth-mating configuration as shown in FIG. 11A, the teeth and the opposite teeth is obliquely contacted, so that when a force is worked from outside owing to vibration or the like, the mating between the teeth and the opposite teeth is unfitted, resulting in that the tape reel 102 is unexpectedly rotated, and the tape becomes readily to be loosened when the tape cartridge is not used e.g. when the tape cartridge is preserved. Thus, if a function for preventing the tape from being loosened is not sufficiently operated and the tape is loosened at an inside of the cartridge case, then the tape will be readily folded and/or jammed.
In order to prevent the tape from being loosened, the teeth are made to be longer and the teeth and the opposite teeth have only to be deeply mated. However, in this case, following working will occur. By pushing up the brake releasing plate 105, the brake-locking member 103 is moved when the tape cartridge is used. Thereby, when the teeth portion 103a of the brake-locking member 103 is detached from the teeth portion 104 at the side of the tape reel 102 as shown in FIG. 11B so that the mating state is released, the gap a becomes narrower between the teeth portion 103a and the teeth portion 104, because the stroke for the releasing is constant while the above-mentioned teeth are long in themselves.
Here, even when the gap a becomes narrower, if the gap a is always kept be constant, there will not occur any big problem. In fact, the brake-locking member 103 is biased against the brake releasing plate 105 using the spring 101 supported by the cartridge case, and the brake-locking member 103 is contacted with the brake releasing plate 105 at a bearing portion 101a whose center portion is convex. Thus, if a pressure balance of the spring 101 is not kept, then the brake-locking member 103 will be inclined. Further, the teeth portion 103a of the brake-locking member 103 is in contacted with the teeth portion 104 of the rotating tape reel 102, because the gap a is originally narrow. Thus, such a configuration might cause an erroneous operation.
Additionally, the bearing portion 101a located at a center of the brake-locking member 103 is rotated and contacted with the brake releasing plate 105 and biased using the spring 101 to receive a pressure. Thus, if a using time of the tape cartridge passes to some extent, the bearing portion 101a may be sometimes worn. The gap a in FIG. 11B becomes narrower owing to such wearing defect, so that the teeth portion 103a is contacted with the teeth portion 104 of the rotating tape reel 102. Thus, in such a same way as above-mentioned, such a configuration might readily cause an erroneous operation.